Overview:
A balloon is placed on a number line from 0 to 1. Students will try to pop it by trying to guess where the balloon rests and throwing a dart at that point. The higher the difficulty setting, the more accurate the guesses will need to be in order to pop the balloon. This is a great activity for reviewing the concept of decimals and how to compare one decimal with another.
NJ Core Curriculum Content Standards:
 4.1.A  Number Sense
 4.1.C  Estimation
Lesson Plan 1
Classroom Environment:
 One laptop or desktop computer and a projector
Materials:
 Internet connection
 Macromedia Flash Player, Version 7 or higher
(Click here to check if it installed. If you come back to this page, you are ok.)
 Some sort of prize for a group of students (optional)
Procedure:
A. Setting the Stage
Review the concept of decimals, especially the difference between the tenths and the hundredths place. You may want to discuss why 0.1 is not the same as 0.01.
B. Activity
 Divide the class into several groups of three to five students.
 Assign a name to each group, or let the students pick their own group names. On a sheet of paper, blackboard, or whiteboard, write down each group's name on a separate row. This is for keeping score.
 Start up the free play version of Decimal Darts, located here, on the projector. Initially, select the level of the game to be 1, with 10 darts, and the scale on.
 You will be going to each group one at a time, so you will need to determine the rotation order.
 Starting with the first group, ask them to guess where to throw a dart in order to pop the balloon. When they have agreed, have one person in the group announce what their guess is, enter it into the game, and throw the dart. If it hits, give that group a point, start a new game, and go on to the next group. If it misses, simply go on to the next group without starting a new game. This way, they have a bit of extra information.
 If the next group hits, they get a point. But if they miss, then just move on to the next group without restarting. Each group will get more of an advantage until the balloon is popped.
 Once all groups have made a guess, start a new game, regardless of whether or not the balloon has been popped. At this point, you may increase the difficulty or turn off the scale, and that setting should remain in effect until every group has had another turn. (If you increase the difficulty all the way up to super challenge with no scale, then it may be a good idea to let each group go 2 or 3 times, since hitting the balloon on the first try at this setting is incredibly hard, and may seem unfair.)
 Proceed in this fashion until you decide it is time to stop the game.
 Check the scores and congratulate the winning team. If you have a prize, let 'em have it!
C. Debrief
Ask the winning team why they did so well and what strategies they used. Discuss any strategies of your own as well.
Assessment:
You can either have the students work on some problems at this point, or, if you have enough computers in the classroom, you can use a modified form of "Lesson Plan 2" in order to get an assessment.
Lesson Plan 2
Classroom Environment:
 Enough laptops or desktop computers to have stations of one to four students each
Materials:
 Internet connection
 Maromedia Flash Player, Version 7 or higher
 Score Sheets (See top left of page)
Procedure:
A. Setting the Stage
Review the concept of decimals, especially the difference between the tenths and the hundredths place. You may want to discuss why 0.1 is not the same as 0.01. If you have a projector, you can do a shortened version of "Lesson Plan 1" as an introduction to the game.
B. Activity
 Divide the class into several groups of one to four students and have each group sit at a laptop or desktop.
 Give each student several score sheets, depending on how many games you want or have time for them to play.
 Direct students to the Activity page  http://www.ciese.org/math/activities/decimaldarts/activity.html
There, they will find a listing of several ways to play the game. It will look like this:
 Lesson 1  10 Rounds, 5 Darts/Round, Scale On.
(Answer Key)
 Lesson 2  10 Rounds, 10 Darts/Round, Scale Off.
(Answer Key)
 Lesson 3  Super Challenge, Shield Around Balloon, 10 Rounds, 10 Darts/Round, Scale Off.
(Answer Key)
 Random Game 1  10 Rounds, 5 Darts/Round, Scale On.
 Random Game 2  10 Rounds, 10 Darts/Round, Scale Off.
 Random Game 3  Super Challenge, Shield Around Balloon, 10 Rounds, 10 Darts/Round, Scale Off.
 Free Play
However, they will not have links to answer keys! For assessment purposes, it would be a good idea to have them do any or all of Lessons 1, 2, and 3. In these games, the balloon is not placed randomly on the scale, and you have answer keys to these games. Thus, students could turn in the score sheets to these games for grading.
 Allow the students to play the games and keep score. Walk around the room and help/question as necessary.
C. Debrief
Ask students or groups with high scores to share why they did so well and what strategies they used. Discuss any strategies of your own as well.
Assessment:
Students may hand in their score sheets for grading.
